Use and maintenance of ball valve of oil tank truck and precautions

The ball valve of tank car is one of the most important parts in the petrochemical industry in China It is easy to operate Now, anlai petrochemical company introduces the use and maintenance of the ball valve of tank car and the precautions In order to maintain the ball valve of the tank car for a long service life and maintenance free period, in addition to normal working conditions, maintaining a harmonious temperature / pressure ratio, and reasonable corrosion data, the following considerations will also be relied on: ● when the ball valve is closed, there is still pressure fluid inside the valve body ● before servicing the ball valve, relieve the line pressure and keep the valve in the open position ● disconnect the power supply or air source before the maintenance of the ball valve of the tank car ● disconnect the actuator from the bracket before maintenance ● it is necessary to find out that the upstream and downstream pipes of the ball valve have been de pressurized before disassembly and disassembly operations can be carried out ● during disassembly and reassembly, care must be taken to prevent damage to the sealing surface of parts, especially non-metallic parts, and special tools should be used when taking out the O-ring ● when assembling the ball valve, the bolts on the flange must be tightened symmetrically, step by step and evenly ● cleaning agent shall be compatible with rubber parts, plastic parts, metal parts and working medium (such as gas) in ball valve When the working medium is gas, the metal parts can be cleaned with gasoline Clean the non-metallic parts with pure water or alcohol ● the individual parts decomposed can be cleaned by immersion cleaning For the metal parts that have not been decomposed, clean and fine silk cloth impregnated with cleaning agent (to avoid fiber falling off and adhering to the parts) can be used for scrubbing During cleaning, all the grease, dirt, glue and dust adhering to the wall surface shall be removed ● after cleaning, the non-metallic parts shall be taken out of the cleaning agent immediately and shall not be soaked for a long time ● after cleaning, they shall be assembled after the volatilization of the cleaning agent on the washed wall surface (it can be wiped by the silk cloth without detergent immersion), but they shall not be put aside for a long time, otherwise they will rust and be polluted by dust ● new parts shall also be cleaned before assembly ● lubricating with grease The grease shall be compatible with metal materials, rubber parts, plastic parts and working media of ball valve When the working medium is gas, for example, te221 grease can be used Apply a thin layer of grease on the surface of the installation groove of the seal, rubber seal and the sealing and friction surfaces of the valve rod ● during assembly, no metal chips, fibers, grease (except for those specified), dust and other impurities, foreign matters, etc shall be allowed to contaminate, adhere to or stay on the surface of the parts or enter the inner cavity 1) If there is micro leakage at the packing, the valve rod nut shall be locked again Note: do not lock too tightly, usually lock another 1 / 4-1 turn, the leakage will stop 2) Replace the valve seat and seal a), disassemble the valve so that it is in the half open position, flush and remove the possible dangerous substances inside and outside the valve body Close the ball valve, remove the connecting bolts and nuts on both flanges, and then remove the valve completely from the pipeline Remove the driving device - actuator, connecting bracket, lock washer, stem nut, butterfly spring piece, gnan, wear-resistant piece and stem packing in sequence Remove the body cover connecting bolts and nuts, separate the valve cover from the valve body, and remove the bonnet gasket Confirm that the ball valve is in the "off" position, which can easily take it out of the valve body, and then take out the valve seat Push down the valve rod from the middle hole of the valve body until it is completely taken out, then take out the O-ring and the lower packing of the valve rod Note: Please operate carefully to avoid scratching the surface of the valve rod and the sealing part of the stuffing box of the valve body B) reassemble the ball valve of oil tank truck, clean and inspect the removed parts, and it is strongly recommended to replace the seat, bonnet gasket and other seals with spare parts package Assemble in reverse order of disassembly Cross lock the flange connecting bolts with the specified torque Lock the stem nut with the specified torque After installing the actuator, input the corresponding signal to drive the valve core to rotate by rotating the valve rod, so that the valve can be opened and closed If possible, please conduct pressure seal test and performance test for the valve according to relevant standards before reassembling the pipeline.